Low body cell mass index in hemodialysis patients: Association with clinical parameters and survival

Body cell mass (BCM) is a useful nutritional marker and is not affected by changes in the hydration status that commonly occur in hemodialysis (HD) patients. This study aimed to examine the association between body cell mass index (BCMI) and nutritional parameters, as well as its relationship with long-term survival in these patients.

This longitudinal prospective multicenter study followed a cohort of patients in HD for 24 months. The clinical parameters of 2527 patients (mean age 70.3 ± 14.6 years, 55.8% male and mean HD vintage 58 (IQR:33-95) months) were measured and their body composition parameters were assessed by a body composition monitor before the HD session. BCM was converted to BCMI (BCM/height² ) and, taking into account the mean value (6.4 ± 2.1 kg/m² ), we split our study population into 2 groups: G1 (BCMI <6.4 kg/m² ; n = 1366) and G2 (BCMI ≥ 6.4 kg/m² ; n = 1161). All statistical tests were performed using SPSS 20.0 software. A P value lower than 0.05 was considered statistically significant.

Patients with a BCMI <6.4 kg/m² displayed higher age (P < 0.001), dialysis adequacy (Kt/V) (P < 0.001), total cholesterol (TC) (P = 0.033), high-density lipoprotein cholesterol (HDL-C) (P < 0.001), relative overhydration (overhydration/extracellular water [OH/ECW]) (P < 0.001), CRP (P < 0.001), fat tissue index (FTI) (P < 0.001) and lower normalized protein equivalent of nitrogen appearance (nPNA) (P < 0.001), albumin (P < 0.001), serum creatinine (P < 0.001), creatinine index (P < 0.001), potassium (P < 0.001), phosphorus (P < 0.001), calcium/phosphorus product (Ca X P) (P < 0.001), lean tissue index (LTI) (P < 0.001) and body mass index (BMI) (P = 0.046). The Kaplan-Meier survival curve showed a significantly better survival in female and male patients with BCMI ≥6.4 kg/m² (P = 0.001 and P < 0.001, respectively). In the cox regression analysis, a significantly higher mortality risk was observed in G1 patients (P = 0.001).

Our study showed that a low BCMI was a mortality predictor and was associated with worse nutritional parameters in patients undergoing HD.